Effect of insulin, cAMP, and dexamethasone on phosphoenolpyruvate carboxykinase gene promoter in vitro / 中国医学科学院学报

ABSTRACT

<p><b>OBJECTIVE</b>To study the effect of insulin, cyclic adenosine monophosphate (cAMP), and dexamethasone (DEX) on 550 bp (-600 -/+ 69) fragment of phosphoenolpyruvate carboxykinase (PEPCK) gene promoter by reporter gene.</p><p><b>METHODS</b>The recombinant pGL2-PEPCK-Luc and the control plasmid pSV-beta-Galactosidase were co-transfected to rat hepatoma cell line (CBRH7919) by lipofectin. By measuring luciferase activity, we evaluated in vitro regulation of PEPCK gene promoter on reporter gene transcription.</p><p><b>RESULTS</b>cAMP and DEX stimulated PEPCK promoter obviously; meanwhile, they also had accumulative effects. At different physiological concentrations, insulin had a suppressive effect on PEPCK promoter, which was dose-independent.</p><p><b>CONCLUSION</b>There is a perfect feedback mechanism for PEPCK promoter in hepatoma cell. 550 bp (-600 -/+ 69) fragment of PEPCK may be a candidate gene in the gene therapy of diabetes.</p>